There are described in the patent literature numerous systems and methods for the recording of X-ray images. Conventional X-ray imaging systems use an X-ray sensitive phosphor screen and a photosensitive film to form visible analog representations of modulated X-ray patterns. The phosphor screen absorbs X-ray radiation and is stimulated to emit visible light. The visible light exposes photosensitive film to form a latent image of the X-ray pattern. The film is then chemically processed to transform the latent image into a visible analog representation of the X-ray pattern.
Recently, there have been proposed systems and methods for detection of X-ray images in which the X-ray image is directly recorded as readable electrical signals, thus obviating the need for film in the imaging process.
For example, U.S. Pat. No. 4,961,209 to Rowlands et al. describes a method for employing a transparent sensor electrode positioned over a photoconductive layer and a pulsed laser that scans the photoconductive layer through the transparent sensor electrode.
U.S. Pat. No. 5,268,569 to Nelson et al. describes an imaging system having a photoconductive material which is capable of bearing a latent photostatic image, a plurality of elongate parallel strips adjacent the photoconductive material, and a pixel source of scanning radiation.
U.S. Pat. No. 5,652,430 to Lee describes a radiation detection panel for X-ray imaging systems which is made up of a matrix assembly of radiation detection sensors arrayed in rows and columns to record static or dynamic images.
Examples of commercially available systems in which X-ray images are directly recorded as readable electrical signals include the Direct Radiography line of detector arrays offered by Sterling Diagnostic Imaging (formerly DuPont) of Delaware, USA, the Pixium line of flat panel X-ray detectors for radiography offered by Trixell of Moirans, France; the Digital Imaging Center offered by Swissray Medical AG of Switzerland, and the Canon Digital Radiography System offered by the Canon Medical Division of Canon U.S.A.
In addition, digital mammographic X-ray systems are commercially available. For example, the Opdima system offered by Siemens Medical Systems, Inc. of New Jersey, USA.